Power lift mfchanism



T. BROWN POWER LIFT MECHANISM Original Filed April 2, 1938 3 Sheets-Sheet 2 INVENTOR. TH-OPH/US @ROW/V ATTORNEY AP 2, -1940- v TQBROWN POWER LIFT MECHANISM Original Filed Aprily 2, 1938 3 Sheets-Sheet 3 Patented Apr. 2, 1940'l PATE POWER LIFT MFC'HANISM 'rheopnum Brown, Moline, n1., mmol-tenure & Company, Moline, lll., a corporation of Illinois Application April z, 193s, serial No. 199,681 Renewed August 21, 1939 ily attached to such a tractor, employing supm porting and driving means which are adapted to cooperate with the usual implement supporting and driving connections, furnished as standard equipment on most tractors. In `the accomplishment of this object, I provide a pair of brackets which are adapted to be fixed to implement mounting bosses formed on the rear face of the tractor axle housing and. which carry the rock shaft and housing containing the power lift mechanism. The primary function of the aforesaid brackets is to support the weight of the power lift attachment and load lifted thereby, and in one of the two embodiments shown and described herein, the tendency of the power lift housing to swing about the axis of the rock shaft during lifting operations is resisted by a stop or abutment which bears against the tractor axle housing. In order to accommodate the power lift housing to irregularities in the surface of the tractor axle housing, and to provideA for properly a aligning the power transmission driving and driven members, the power lift housing is made rockable about a transverse axis so that the angular relation between the power lift and axle housings can be changed, while the aforemen- .5 tioned stopcomprises a set Screw in threaded engagement with a lug formed on the power lift housing. Since practically all modern tractors are provided with a projecting splined power take-off shaft as standard equipment, my invention contemplates using this as the source of power. Accordingly, a splined sprocket readily attachable to the power take-off shaft is employed, with a chain drive to transmit power to a the lifting mechanism.

Another object of the present invention is to provide a power lift attachment adapted to be mounted on the implement mounting means of tractors, employing a pair of lifting units driven 50 by the implement driving means and capable of independent or simultaneous operation, at option.

These and other objects and advantages of the present invention will become apparent after a consideration of the following detailed descriplo tion of the preferred structural embodiment, ref- The present invention relates to power lifterence being had to the accompanying drawings, in which: v f

Figure 1 is an elavational view of my improved power lift attachment mounted on the rear axle housing of a tractor; l n Figure 2 is a left side view of the construction shown in Figure 1, with the ne'ar lifting arm removed to show certain details more clearly, and a portion of the gear drive shown in dotted lines; Y

Figure 3 is a right side view of the same 'structure, also with the near lifting arm removed;

Figure 4 is a side view, drawn to reduced scale, H I

of a portion of a tractor with attached power lift l mechanismand a planting implement, showing 6 the manner of connection between the lifting mechanism and implement as well as the driving connection between the auxiliary power takeoff driving member and the implement planting mechanism, the near tractor wheel as well as various other parts of the power lift mechanism and implement being removed or omitted for the sake of clarity;

Figure 5 is a rear elevation of another embodiment of the present invention, in which two lifting units are employed and in which the structural form of the housing and supporting brackets has been modified;` the sprocket and chain transmission drive being identical to that shown in Figures 1, 2 and 3 and therefore indicated 30 only diagrammatically here; and

Figure l6 is a side elevation of the embodiment shown in Figure 5. l

Referring now to the drawings and moreparl ticularly to Figures 1 to 4, inclusive, the numeral 95 Hl indicates a `banjo type axle housing containing the rear axle and differential mechanism of a more or less conventional tractor, and closing the usual rear opening is a cover plate il. As is customary in most present day tractors, the back side of the axle housing Illl is provided with laterally spaced, rearwardly facing implement mounting bosses I0 disposed generally symmetrically on opposite sides of the cover plate I |,to which brackets, draft connections, and. other` suitable complementary connecting means associated with various detachable implements may be bolted or otherwise suitably secured; In the embodiment illustrated herein, the power lift attachment comprising the present invention is mounted on the bosses l0' by means of two vertically extending angle iron brackets l2 and I3, the latter of which is curved inwardly to avoid certain operating mechanism as will readily be seen in the drawings. Preferably, although not necessarily, the manner of connecting the brackets I2, I3 to the bosses I0' is similar to that described in detail in the co-pending application of Theophilus Brown and Talbert W. Paul, Serial No. 183,067, filed January 3, 1938, in which stud bolts Il are screwed into vertically spaced threaded recesses in each of the bosses I5 and provided on their outer ends with hexagonal or other suitably shaped cap nuts I3. The brackets I2 and I3 are provided with vertically extending keyhole slots having a lower circular portion I9 of sufilciently large diameter that will permit the cap nuts I 8 to pass through such portion, anu an upper generally rectangular shaped portion of reduced width communicating with and extending upwardly from the portion I3 to receive the shank of the stud bolt I1. e

It will be seen from the above that in order to install the supporting brackets I2 and I3 on the rear axle housing it is only necessary to unscrew the cap nuts I8 on the studs I 'I to move them away from the boss a sume-lent distance to permit the bracket to be inserted between such cap nuts and the boss, and then the bracket can be slipped over the cap nuts I8 and dropped into place on the studs II, after which the cap nuts are drawn up on the studs I'I to clamp the brack ets I2 and i3 securely in place against the faces of the bosses ID.

The upper end of each of the bracket members I2, I3 is provided with a socket portion I 4, and cradled in these sockets is the transversely extending upper tubular portion I5 of a mechanism housing, indicated in its entirety by the reference numeral I6. The brackets I2 and I3 are each provided with a clamp comprising a curved link 20 which is swingably connected to its respective bracket by a pivot bolt 2|. A bolt 22 in threaded engagement with the free end of the link 20 is adapted to be clamped down against the top surface of the tube I5 to hold the latter down into the sockets I4, while a lock nut 2l serves to hold the bolt 22 against loosening. Disposed below the tube I5 and parallel thereto is a second shorter tube 23, the left end of which terminates in a gear case 24 and the right end of which terminates in a clutch housing 25. Interconnecting the two tubular portions I5 and 23 are two arms 26 and 30 which are formed integrally with the tubes I5 and 23 providing a strong and rigid housing to hold the mechanism to be described hereinafter.

Journaled within the transversely extending tube I5 is a rock shaft 3|, the ends of which project laterally outward beyond the ends of the tube I5 and are squared, as at 32, to engage a square aperture formed in the hub of a lifting arm 33. Journaled in the lower tube 23 is another transverse shaft 34 which also extends beyond the ends of the tube, and xed on the left end of the shaft 34 by means of a set screw 35 is a sprocket 36, the purpose of which will be disclosed later.

As previously stated, the left end of the tube 23 terminates in a gear case 24, and fixed on the shaft 34 within this gear case is a worm gear 40, as shown in dotted lines in Figure 2. Disposed below the gear 40 in driving relation therewith is a worm 4I fixed on a shaft 42 which is suitably journaled in the gear case 24 and projects rearwardly therefrom. Driving the shaft 42 through a conventional slip clutch 43 is a sprocket 44 disposed on thel rear end of the shaft 42 and adapted to receive power from the tractor power take-off shaft in a manner to be described shortly. Preferably, although not necessarily, the slip clutch 43 comprises a pair of companionate serrated collars 45 and 4l, the first of which is fixed to the shaft 42 and the other of which is fixed to the adjacent face of the sprocket 44 which is Journaled on the shaft 42. A compression spring 55 bearing against a retaining washer 5I and lock nut 52 threaded on the end of the shaft 42, holds the sprocket and collar 4I against the collar 4l with sufficient force to resist any tendency for relative movement between the two elements under normal load. When overloaded, however, as by attempting to lift too heavy an implement orv when the implement lifting means become jammed, the forces set up by the co-acting surfaces of the serrated collars 45, 46 exceed the force exerted by the spring 50 causing the sprocket 44 to rotate on the shaft 42 and at the same time slide back and forth thereon as the collar 45 rides over the high points on collar 45.I

In the conventional tractor as illustrated herein, the power take-olf shaft comprises a splined shaft 53 projecting rearwardly from a suitable housing disposed substantially centrally in the lower portion of the cover plate II, and engaging the splines of the shaft 53 is a sprocket 54. The latter is quickly and easily slipped on or oil the power take-oil.' shaft 53 and is held in position thereon by means of a set screw 55 which is in threaded engagement with the hub of the sprocket 54. A driving chain 56 is trained over sprockets 44 and 54 and held tight by a chain tightener comprising a sprocket 6I journaled on an arm 62 which is swingably connected by a pivot bolt 63 to a bracket 54 formed on the gear case 24 and yieldingly held against the chain 56 by a tension spring 85. The latter is hooked at its other end through an aperture in a lug 65 formed on the under side of the tube 23.

Disposed within the clutch housing 25 is a self-interrupting, half-revolution type clutch 61 of conventional design well known to those vskilled in the art and therefore not shown in more detail here. Briefly, the clutch 51 comprises a driving member (not shown) which is fixed to the normally rotating shaft 34; a driven member l0 journaled on the shaft 34 and having a radially extending flange II disposed on the outside of the clutch housing 25; and means for optionally engaging and automatically disengaging the driving and driven clutch members after a half revolution together. The last named means includes suitable mechanism carried on the clutch driven member 'IIJ within the housing 25 for locking the driving and driven members together and is actuated by a lever arm 'I2 which is pivotally connected to the driven member 'I0 by a pivot bolt 13 and with its ends positioned adjacent a pair of spaced notches 'I4 formed in the flange ll in a manner best illustrated in Figure 3. A roller 'I5 which is normally seated in one or the other of the notches I4 bears against the lever arm 'I2 disabling the locking mechanism within the clutch until the roller is lifted out of its seat in the notch, at which time the clutch is engaged causing the driven member 1I! and attached lever arm 12 to rotate through 180. As the succeeding notch 'I4 comes around into position, the roller 15 drops into seating engagement with it, thereby disabling the locking mechanism once more.

The roller 'I5 mentioned previously is carried between and journaled in the ends of a pair of spaced parallel members 'Il which extend upwardly and forwardly therefrom to form the right leg of a U-shaped trip bar Il. Welded between the membersn a esattamente-abbatte nner" 15 is av-block 3| whichv extendsdownwardly'andy curves forwardly up over' the tube vI5 where it is bent to form the transverse portion of the trip bar 80vwithin easy reach 'of either foot of the .tractor operator. The Ileft leg 84 of the trip bar 'I 30 is likewise curved downwardly and pivotally connected by a pin 65 to a lug- 06 formed on the back side of the tube I5, the pin 34 being disposed in axial alignment with pin 02. A tension spring I fastened at one end to a lug 9| formed on the side of the'housing arm 30 and hooked at the other end through the eye of an eye bolt 02 which is passed through aligned holes in the members 16 between the pin 82 and roller 15 exerts a yielding force against the trip bar 80 to hold ,the roller against the ange 1|.

' Transmitting the liftingforce from the clutch i 66 to the rock shaft 3|,.is a link 93l the lower end of which is journaled on a crank 94. projecting laterally from theVclutch driven member 10. The upper end of the link 03 is bifurcated to receive a lever arm 95 which is fixed as by welding to the rock shaft 3|, and the levery arm 95 and link 93 are swingably connected byda pin 96 passed through' aligned apertures in the two members. Thus it will vbe seen that the operation of the clutch 66 causes the rock shaft l3| to be rocked between two terminal positions'in which the lifting arms 33 are raised or lowered.

In mounting'the power lift attachment on a tractor, the'rst step is to secure the bracket members I2 and |3onto the rear axle housing. The clamp links are then swung downwardly out of the way and the housing lifted up onto the brackets and seated in the socket portions |4. I'he sprocket 54 is then slipped over the splined power takeoff shaft 53 and the chainy 56 trained over both sprockets. If it is found that the two sprockets 44 and54 cannot be made to lie in the same plane due to improper contact of the houst ing l0 against the cover plate the lower tube 23 can be` moved forwardly or rearwardly 'relative to the upper tube |-5 by means of adjusting screws |00 which are in threaded engagement with lugs 66 and |0| formed on theunder side W of the tube 23, and which bear against the cover plate il. causes the lower tube 23 to move rearward rela-- tive to the upper tube l5, vchanging'theangleV of `txie plane of the sprocket 44 and `making it ypossible to align both sprockets 44` and 54 inthe same plane. When the sprockets havebeen properly aligned, sprocket 54 is clampedv in'pos'ition on the power takeoff shaftv53 through the agency of the set screw 55, and the chainftightener sprocket 6| is engagedwth the underv side of the lower run of the chain 56. At this point the links. 20 are swung up into position and clamped vdown upon the upper tube l5 with sumcient force to prevent any tendency of the housing `I6 'to swing back and-forth when notjunder load. v

l Figure 4 illustrates one application of my power q lift attachment in which a tractor `mounted planter, indicated generally by the reference nu# meral |02, utilizes both the lifting mechanism 'a and power take-oil` drive. Draft connection between the planter |02 and tractor comprises two laterally spaced'pairs of parallel links |03 which arefswingably connected at their front lends to brackets fixed on the outer ends of the rear axle u housing and at their rear ends to. .a bracket d aneaoss'g l 3 l ,A member m commette forward end-biene.. V'planter standard. A transverse bar-. |05;,extendejfl ving between and suitablyjxed lto thetwo lower links l|||3 is connected-byfchains |06to the-two Turning the adjusting screws |00 in l lifting arms 33.. lThe planting'v mechanism indi'- cated aty |01 is actuated by a drive shaft |03 and the latter is provided with a sprocket xed therej to `which is driven through chain transmission- |09 and countershaft ||0 from the power take-off driving sprocket 36. The countershaft ||0 extends transversely between the planter bracket members |04 and is journaled therein in the same position relative to the rear ends of the links |03 as is the sprocket 36 relative to the front ends of the links |03 so that the distance between the sprocket 36 and countershaft ||0 remains constant regardless of the vertical movement of the planter |02 relative to the tractor. A chain trained over sprocket 36 and a sprocket fixed on the shaft ||0 drives the latter, while a chain ||2 transmits power from the countershaft ||0 back to the drive` shaft |08. i

Figures 5 and 6 show another embodiment of the present invention employing two lifting n clutches which are operable independently or simultaneously, at option, together with a modified housing and supporting structure.

As in the previously shown embodiment, the power lift attachment comprises a housing ||1 in which is contained operating mechanism driven by power derived from the power take-off shaft of the tractor, said housing being connected to suitable implement mounting means provided on the rear axle housing of the tractor through the agency of two laterally spaced, upright angle iron brackets ||3 and H4. Each of the brackets H3, |4 is made up of two perpendicularly disposed flanges; bracket ||3 comprising flanges l|5 and H6, and bracket 4 comprising flanges H5' and H6. Flanges ||5 and H5 are adapted to be clamped to the faces of bosses I0', and to this end each is provided about midway of its lengthl with a vertically extending keyhole slot identical to those formed in bracket members i2 and |3 of the embodiment shown in Figure l. The lower ends of the flanges ||5, ||5' differ from 'the rst shown embodiment, however, in that each is provided with an open ended vertically extending slot |20 that is adapted to fit over the lower stud bolt-|1 behind its vcap' nut I8, such construction lfacilitating Amounting `and demounting of 'the attachment under certain. conditions. Y

ly, Amember-123 is made up as a'- casting, being provided with aflange portionv adapted'to be xed yto the inner side of flangev H6 as by bolts |25,

and a coverv plate portion |26 adapted to ycooperate with the open end of the gear case |22. Member |24 is likewise xed to flange I6 in any vsuitable manner and is secured to lugs |3| provided at'the right'end of the tube |2| by means of bolts |30. Disposedvwithin the tubular portion |2| and journaled in suitable bearings therein is ashaft |32 to which is fixedl a worm gear |33. 'A rearwardly extending shaft |35 having an integral worm |34 is journaled in theV housing l l1 ,'below the gear |33 and operatively engaged' therewith to drive the latter; shaft |35 being driven, in turn, from the power take-off shaft 53 through a sprocket and chain driveV and a slip clutch, indicated diagrammatically at IBL-" which are identical to those shown in greater detail in Figures 1, 2 and 3.

Disposed at opposite ends of the shaft |32 are two self-interrupting lifting clutches and |4| similar to the clutch 61 described in the embodiment shown'in Figures 1, 2 and 3, and each having a flanged driven member |42 provided with notches |43 in one of which the actuating roller |44 is normally seated. As previously explained, unseating the roller from its socket initiates the operation of the clutch, causing the driven member to be rotated through substantially one half revolution, at which point the mechanism automatically disengages the clutch driving and driven members. Each of the rollers |44 is carried in a trip lever |45 which is pivotally connected by a pin |46 to the outer side of flanges ||6 and ||6, respectively, and extends upwardly and rearwardly therefrom to a bifurcated supporting member |50, in which the roller |44 is journaled. From the supporting member |50, the levers |45 curve forwardly, upwardly, and inwardy, terminating in a pair of foot pedals |5| and |52 which are disposed side by side within easy reach of the operator's feet. Depressing the left pedal |5| operates the left clutch |40, and likewise, depressing the right pedal |52 operates the right clutch |4|. Means have also been provided for operating both clutches simultaneously with either foot, comprising a bail having a transverse portion |53 disposed above and resting upon the forwardly extending portion of both trip levers |45, and a pair of downwardly bent legs |54 which are pivotally connected at their ends by pins |46 to the inner sides of flanges ||6 and ||6', respectively. Thus it will be seen that by stepping upon the transverse bar |53 at any point along its length, both trip levers |45 are depressed, causing simultaneous operation of both lifting clutches |40 and |4|.

The lifting force exerted by the clutches |40 and |4| is applied to two bell cranks |55 and |56 which are rockably supported in bearing blocks |60 fixed to the upper ends of the brackets ||3 and ||4. Each of the bearing blocks |60 comprises a transverse sleeve portion 6| and a downwardly and forwardly extending 'bracket portion |62 having two perpendicularly disposed flanges which are adapted to fit up against the flanges ||5, ||6 and ||5, ||6, respectively, and are bolted thereto by bolts |63. A pin bolt |64 is passed through aligned apertures in each of the bell cranks |55, |56 and thei'r respective sleeves |6|, provided bearing means upon which the bell cranks are free to rock independent of each other. A link |65 which is pivotally connected at one end to a crank |66 on the clutch driven member |42, and at the other end to a pin- |10 extending laterally inward from the end of one of the bell crank arms |1|, provides the connecting and power transmitting means betweeneach of the clutches |40, |4|, and their respective bell cranks |55, |56. 'A second'bell crank arm |12 extending generally upward at substantially a right angle to arm |1| is adapted to operate lifting means on forwardly mounted cultivator rigs or other implements carried on the 4 tractor frame ahead of the rear axle housing.

A lug |13 vprojecting laterally outward from the edge of the bracket portion |62 of the bearing block |60 provides a base 'adapted to receive and hold one end of a compression spring |14 which -bears against a suitable lug |15 formed on the trip bar |45 adjacent the trunnion |50 to hold the roller |44 yieldingly against the flanged clutch member |42 and to return the pedals Ill and |52 to their normal positions when released after being depressed.

What I claim is:

1. In combination with a tractor having a body provided with connecting means adapted to cooperate with complementary detachable implement connecting means, a power lift attachment including a housing, means adapted to cooperate with said tractor body connecting means for supporting said housing, power lift mechanism disposed within said housing, and detachable means for operatively connecting said power lift mechanism with the tractor driving means.

2. In combination with a tractor having a body including a transversely disposed rear axle housing provided with laterally spaced supports adapted to receive complementary detachable supports connected with implements interchangeably associated with said tractor and an engine driven power take-off shaft projecting from said tractor body for supplying rotative power to said associated implements, a unitary power lift attachment including means cooperative with said laterally spaced supports for detachably mounting said power lift attachment on said tractor, and a detachable driving connection between said power lift attachment and said power take-oi! shaft.

3. In combination witha tractor having a body including a transversely disposed rear axle casing provided with at least two laterally spaced implement mounting bosses and an engine driven power take-ofi' shaft projecting rearwardly from said body, a power lift attachment for said tractor comprising a housing, mounting means for said housing adapted to cooperate with said implement mounting bosses for detachably supporting said power lift attachment on said tractor, power lift mechanism disposed within said housing, and detachable means for driving said power lift mechanism from said power take-off shaft.

4. In combination with a tractor having a rear axle housing and a power take-off shaft, a power lift attachment comprising a pair of laterally spaced bracket members adapted to be fixedly secured to said axle housing, a mechanism housing supported on said bracket members, a transverse rock shaft journaled in said mechanism housing, a transverse drive shaft journaled in said mechanism housing below and parallel to said rock shaft, a worm gear fixed on said drive shaft, a worm positioned in driving relation with said gear, self-interrupting clutch mechanism actuated by said drive shaft and operatively connected with said rock shaft to rock the latter, and driving connection between said power takeoff shaft and said worm.

5. In combination with a tractor having a frame and a rearwardly extending power takeoff shaft, a power lift attachment comprising a pair of laterally spaced bracket Ymembers fixedly attached to said frame, a housing supported on said brackets for swinging about a transverse axis, a rock shaft journaled in said housing, operating mechanism disposed within said housing for rocking said rock shaft, means for driving said operating mechanism from said power take-off shaft including a driving member fixed to said power take-off shaft and a driven member journaled in said housing for rotation about an axis parallel to said power take-olf shaft, and means for aligning said driven member parallel to said power take-oli? shaft comprising an adjustable stop on said housing spaced vertically from said transand adapted to supply power to saidv associatedframe toprovide'for angular adjustment-of said housing relative to said power. take-0H shaft.'

6. In combination with a tractor' havinga body. including a rear axle housing provided with spaced connecting means adapted to cooperate with complementary connecting means of associated implements for detachably mounting the latter on said tractor body and an engine driven power take-off shaft projecting from said body implements, an attachment comprising a mecha.- nism housing havingv mounting means adapted to cooperate with said axle housing connecting means, a drive shaft journaled in said mechanism housing, power lift mechanism disposed at one end of said drive shaft and operatively connected therewith, a power take-off driving member fixed to the other end of saiddrive shaft, and driving means operatively connecting said drive shaft with power take-off shaft.

7. In combination with a tractor having a transversely disposed rear axle housing provided with laterally spaced supports adapted to receive complementary detachable implement supports, a unitary power take-off attachment comprising a mechanism housing and a transverse power take-off shaft journaled therein, means cooperative with said laterally spaced supports for detachably mounting said lpower lift attachment on said tractor, and detachable means for operatively connecting the tractor driving means with said power take-off shaft to drive the latter.

8. In combination with a tractor having a transversely disposed rear axle housing provided with laterally spaced supports adapted to receive complementary detachable implement supports, and a rearwardly projecting engine driven power take-off shaft, a unitary power take-oil.' attachment comprising a supporting structure, a transverse power take-off shaft journaled in said supporting structure, means cooperative with said laterally spaced supports for detachably mounting said attachment on said tractor, and a detachable driving connection between said transverse power take-off shaft and said rearwardly projecting tractor power take-.off shaft.

9. In combination with a tractor having a power take-off shaft and a generally transverse rear axle housing provided with a pair of spaced implement mounting bosses adapted to cooperate with complementary detachable implement connecting means, a power lift attachment including a second housing having bracket members adapted to be fixed to said implement mounting bosses, a shaft journaled in said second housing, a pair of power lift units disposed at opposite ends of said shaft and operatively connected therewith, a worm gear fixed to said shaft, a worm disposed in driving relation with said worm gear, detachable means for driving said worm from said power take-off shaft, control means for operating each of said power lift units independently, and control means for operating both of said power lift units simultaneously.

10. In combination with a tractor having a rear axle housing provided with a pair of laterally spaced implement mounting bosses and an engine driven power take-off shaft, a unitary power lift attachment comprising a mechanism housing having a transverse tubular portion, a pair of bracket members adapted to be detachably xed to said implement mounting bosses, means for supporting said mechanism housing on said bracket members, a shaft journaled in said transclutches disposed at opposite ends of said shaft andoperativel'y connected therewith, power ltransmission means operatively connecting 'saidl shaft with saidlpower take-oifshaft, a.- pair of bell..

cranks, supported onY s aid bracket members'forrocking about a transverse axis, link means connecting each o fsald clutches 'with its respective- .verse tubular portion, a pair of self-interrupting bell crank,` and control means for operating said clutches independently or simultaneously atoption.

11. The combination,` with a tractor having a pair of power'lift" units of the type each 'comprising a driving member, .a driven member, locking means for engaging said driving member with said driven member, and actuating means including a trip lever pivoted for swinging about a transverse axis and operatively engaged with said locking means, each of said trip levers having a forwardly extending portion adapted to be depressed, of control means for operating both of said actuating means simultaneously, said control means comprising a bail member pivoted for swinging about a transverse axis and having a transverse portion disposed above and resting upon the forwardly extending portions of both of said trip levers, whereby depressing said bail member depresses both of said trip levers simultaneously. Y

12. In combination with a tractor having a power take-off shaft and a generally transverse rear axle housing provided wlthspaced implelment mounting means adapted to cooperate with complementary detachable implement connecting means, a power lift attachment including a second housing having bracket members adapted to be fixed to said implement mounting means, a shaft journaled in said second housing, a pair of clutch units disposed at opposite ends of said shaft and operatively connected therewith, said second housing having an enlarged section for housing drive gears, a worm gear in said enlarged section and fixed to said shaft, a worm disposed within said enlarged section and in mesh with said worm gear, and detachable driving means for driving said worm from said power take-off shaft.

13. A power lift attachment of the class described, comprising in combination, a housing including a pair of vertically spaced tubular portions rigidly interconnected by bracing members, means for supporting said housing on a tractor, a drive shaft journaled in one of said portions and a rock shaft journaled in the other of said portions, a driving gear mounted on said drive shaft, means for operatively connecting said gear with the tractor engine, self-interrupting clutch mechanism mounted on said drive shaft, and link means connecting said clutch mechanism with said rock shaft.

14. A power lift attachment of the class described, comprising in combination, a housing including a pair of vertically spaced tubular portions rigidly interconnected by bracing members, bracket means for supporting said housing on a tractor, a drive shaft journaled in one of said portions and a rock shaft journaled in the other of said portions, said drive shaft portion having an enlarged section for housing a drive gear, a drive gear in said drive gear section and fixed to said drive shaft adjacent one end of the latter, the opposite endv of said drive shaft extending out of said tubular housing, self-interclutch mechanism with said rock shaft, and means for operatively connecting said drive gear with the tractorengine.

15. A power lift device for use on a tractor, comprising in combination, a rock shaft, supporting means therefor including bearing means mounted on the tractor in which said rock shaft is journaled, an arm fixed to said rock shaft, engine driven lifting mechanism connected to said arm to actuate the rock shaft by power from the tractor engine, and means for supporting vsaid lifting mechanism from said bearing means.

16. A power lift device for use on a tractor, comprising in combination, a rock shaft, supporting means therefor including bearing-means mounted on the tractor in which said rock shaft is journaled, an arm xed to said rock shaft, engine driven lifting mechanism disposed below said rock shaft and connected to said arm to actuate the rock shaft by power from the tractor engine, and means for swingably suspending said lifting mechanism from said bearing means.

17. In combination with a tractor, a power lift rock shaft, supporting means fixed to said tractor for rotatably supporting said rock shaft, an arm on said rock shaft, a lifting device disposed below said rock shaft and connected to said arm, power transmitting means operatively connecting said device with the tractor engine, and a supporting member attached to said lifting device and extending upwardly therefrom, the upper end of said member being attached to said rock shaft supporting means.

18. In combination with a tractor, a transversely disposed power lift rock shaft, supporting means therefor including a pair of laterally spaced brackets attached to the tractor, a lifting device disposed adjacent said rock shaft and connected thereto to rock the latter, power transmitting means for actuating said lifting device by power from the tractor engine, and supporting means for said lifting device connected between the latter and at least one of said brackets.

19. In combination with a tractor, a power lift rock shaft, supporting means therefor including at least one bracket detachably nxed to the tractor, an arm on said rock shaft, a lifting device disposed below said rock shaft and connected to said arm, power transmitting means connecting said device with the tractor engine, a supporting member attached to said lifting device, and means for attaching said supporting member to said bracket.

20. In combination with a tractor, a power lift rock shaft, supporting means therefor including at least one bracket detachably fixed to the tractor, an arm on said rock shaft, a lifting device disposed below said rock shaft and con- ,nected to said arm, power transmitting means connecting said device with the tractor engine, a supporting member attached to said lifting device, means for attaching the upper end of said member to said bracket, and means connected with said lifting device and reacting against the tractor during actuation of the lifting device. 21. In combination with a tractor, a power lift rock shaft, supporting means therefor including at least one bracket fixed to the tractor. an arm on said rock shaft, a lifting device connected to said arm, means supporting said lifting device on said bracket, and means for actuating said lifting device by power from the tractor engine including a flexible power transmitting member connecting said lifting device with a continuously rotating part on the tractor. 22. In combination with a tractor, a power lift rock shaft, supporting means therefor including at least one bracket detachably fixed to the tractor, a lifting device spaced from said rock shaft and operatively connected to rock the latter, supporting means attached to said lifting device and connected to said bracket, said lifting device being swingable relative to the tractor, and means for actuating said lifting device by power from the tractor engine including a detachable flexible power transmitting member connecting said lifting device with a continuously rotating part on the tractor.

THEOPHILUS BROWN. 

